Method of making front terminal battery connection

ABSTRACT

1. A method of making a battery terminal connection through an opening in a opening in a battery case wall comprising positioning a first member on one side of said wall, said first member having a main body section and an extending section adapted to be positioned in said opening, placing said extending section in said opening and through said wall with a portion of said section projecting from the opposite side of said wall, placing a second member, said second member being fabricated with an accommodating compartment for fictionally engaging said extending section of said first member, fluidizing with force the contacting portions of said first and second members plasticizing a portion of said wall between said first and second members, permitting the fluidized contacting portions to cool and forcing said first and second members together with a portion of said fluidized wall in between.

Oct. 22, 1974 n. ORLANDQ ETAL 3,843,411

METHOD OF MAKING FRONT TERMINAL BATTERY CONNECTION Filed larch 14, 1973 4 Sheets-Sheet 1 Pam c455 @4676 ,drron/ Fem 7' Burro/v MEC'H4/V/CAL M 557- Pee-saves 72s;-

Oct. 1974 QRLANDQ ETIAL 3,843,411

METHOD OF MAKING FRONT TERMINAL BATTERY CONNECTION Filed March 14, 1973 I N 4 Sheets-Sheet, 2

Oct. 22, 1974 p, ORLANDO A 3,343,411

METHOD OF MAKING FRONT TERMINAL BATTERY CONNECTION Filed march 14, 1973 I v 4 Sheets-Sheet s i0 I Z 92 l- I ll I I I H Oct. 22, 1974 Y D. ORLA-NDO HAL 3,843,411

METHOD OF MAKING FRONT TERMINAL BATTERY CONNECTION Filed March 14, 1973 4 Sheets-Sheet United States Patent O 3,843,411 METHOD OF MAKING FRONT TERMINAL BATTERY CONNECTION Daniel Orlando, New Berlin, Walter Carl Kirchberger,

Menomonee Falls, and John Clark Ware, Jr., Milwaukee, Wis., assignors to Globe-Union Inc., Milwaukee,

Wis.

Filed Mar. 14, 1973, Ser. No. 341,230 Int. Cl. Hlllm /00 U.S. Cl. 136135 S 11 Claims ABSTRACT OF THE DISCLOSURE A method of fabricating a front or side wall terminal for a battery of the lead acid type. Two button-like members are welded together through the casing wall of a battery container wherein a hole is first provided. One of the button members has an extending cylindrical portion which fits into and through the hole and the other button member has a compartment which partially accommodates the extending cylindrical portion. The two members are welded together by a ram welder and after a predetermined time are squeezed together by a mechanical upset procedure. In a preferred method, an annular wax bead is provided on the first member where it contacts the adjacent surface of the wall near the opening. A nut with a threaded plug is provided in the first button to later afford a threaded terminal construction.

CROSS REFERENCE TO RELATED APPLICATIONS (None).

BACKGROUND OF THE INVENTION This invention relates to a method of fabricating a connection in a lead acid storage battery and more particularly, to a side or end wall terminal construction of the metallic type which is secured through a wall composed of a plastic material such as polypropylene.

With the advent of side or front terminal connections for lead acid storage batteries, problems have arisen as these connections are by necessity made below the electrolyte level of the battery. To avoid damage from the electrolyte acid, a leakproof connection is mandatory. This is a problem in the lead acid storage battery casing utilized today in that many of them are composed of a plastic composition such as polypropylene. The connections themselves are usually made of metal and in most instances are fabricated from a lead alloy. Care must be taken not only to assure that proper fusion of the metal parts is effected but that a fluid tight seal is created between the metal terminal construction and the plastic wall. In most instances, the fusion of the metal part mem hers is accomplished by welding. When the welding is accomplished in the vicinity of a plastic wall, extreme caution is necessitated in that the plastic can become so fluid that it will literally run away from the metal parts. This, of course, results in an improper terminal as well as one which will leak. The prior art nowhere offers a solution to this problem in a manner which will afford a rigid and leakproof construction for a side or front wall terminal battery.

It is an object of the present invention to provide a method of fabricating a side or front wall terminal for a lead acid storage battery. It is another object of this invention to provide a terminal construction for a lead acid storage battery which is disposed below the electrolyte and affords a leak resistent connection. It is still another object of the present invention to provide a threaded metallic terminal construction for a lead acid storage 3,843,41l Patented Oct. 22, 1974 storage battery which can be effected in a semi-automated manner.

SUMMARY OF THE INVENTION The foregoing objects are accomplished and the shortcomings of the prior art are overcome by the present method of making a battery terminal connection wherein a first button-like member is positioned in and through an opening in an external wall of a battery container. A second member is placed in contact and surrounds a portion of the first member button on the opposite side of the wall. The two members are fused by means of ram welding and after a short cooling period are mechanically upset by a swaging action. In the preferred manner, an annular wax head is applied around the first member in contact with the wall prior to the welding and swaging.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the present method for a terminal construction for a lead acid battery will be accomplished by reference to the drawing wherein:

FIG. 1 is a flow diagram illustrating the procedural steps utilized in the present method.

FIG. 2 is an exploded view illustrating the two button members prior to placement in an opening in a battery container wall.

FIG. 3 is a view in vertical section showing the two button members fused in a fluid tight engagement in the battery wall.

FIG. 4 is a view in vertical section illustrating one method of casting a threaded nut in one of the button members.

FIG. 5 is a view in vertical section similar to that of FIG. 2 but showing the alignment of the button members prior to fusing.

FIG. 6 is a diagrammatic view illustrating a method of applying a wax bead to one of the button members.

FIG. 7 is a partial view in side elevation illustrating a ram type welder for use in the method of this invention.

FIG. 8 is a view in side elevation illustrating an apparatus for performing the mechanical upsetting or swaging step.

FIG. 9 is a schematic view illustrating a gun-type welding device for welding a strap button member to the disk on the inside of the battery case.

FIG. 10 is an exploded view illustrating a preferred connection for welding a strap button member with the usual plates to the inside disk and the inside disk for connection with the outside button.

FIG. 11 is a View in vertical section of the completed connection of the components indicated in FIG. 10 and utilizing the process of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred manner of producing a passage or hole in the side or endwall of the battery casing and through which the terminal construction of this invention is made is provided by a punch apparatus described in U.S. 3,238,- 829. This punching step is diagrammatically illustrated in FIG. 1 which also shows the basic steps for accomplishing the front terminal construction of this invention. The type of battery case or container which is employed in this invention is that described in U.S. Pat. 3,388,007. A portion of the battery side or endwall 11 for the plastic case is shown in FIG. 2 and has an annulus 12 surrounding an opening 14 which will have been provided by the previously described punching apparatus. A front button member is cast from a lead alloy such as 3% antimony-lead and is shown at with a steel nut 38 and a threaded plug 39 cast therein. Button 15 has an extending section 16 which is generally cylindrical for placement in and through opening 14. A back disk 18 which may be composed of the same lead alloy as front button 15 is circular in configuration and has an accommodating circular compartment 19 for frictionally engaging a portion of the extending section 16 which projects through passage 14 and beyond the back of wall 11.

'Prior to placement of front button 15 within annulus 12 and through passage 14 an annular wax bead 20 will be applied to front button 15 in the region where the extending projection 16 projects from the main body sec tion 17. The bead 20 is composed of a thermoplastic composition and has a melting point of 350-375 F. After the application of the wax-like bead 20, the front button 15 will be placed within annulus 12 and with the extending section 16 projecting through passage 14 and on the other side of wall 11, back disk 18 will be frictionally placed over a portion of extending section 16 which projects from the passage 14. In this position, the front and back buttons which are in contact will be fluidized while under force such as by means of a ram weld operation. This force is effected in two stages with an initial force of 460 pounds and then an increased force of 200 pounds while the welding current and forces are applied from the front of front button 15 and from the back disk 18. In this instance, the forces are applied for 56 cycles (56/ 60ths of a second) and the weld time is set at 26 cycles (26/ 60ths of a second). The welding current is applied 30 cycles after the force is initiated and terminated 1.5 seconds before termination of the period during which the force is effected. A welding current of 16,500 amps isutilized and is controlled in a manner so as not to melt away the surrounding plastic wall 11 adjacent the opening 14. After a period of 2 minutes which will permit a cooling of the front and back buttons as well as the plastic wall 11 but while the surrounding wall is in a plasticized condition, a force of 4000 pounds will be applied from the front of button 15 and against the back of button 18 so as to squeeze or mechanically upset these two button members together with wall 11 disposed therebetween. This upsetting or swaging will be effected in 1.5 seconds.

To assure that a fluid tight connection has been made, the terminal construction, as ultimately fabricated and as shown by the numeral 23 in FIG. 3 will be subjected to a leak testing procedure which employs the placement of a solution over and around the button 15 as well as annulus 12 and pressure applied inside the battery container with a cover disposed on the top. Any leak will be evidenced by bubbles appearing in the leak test material. After a leakproof terminal construction is afforded, an upstanding lug which will be fabricated on a battery strap by a cast on method described in U.S. 3,087,005 will be welded with force to the back of back button 18 to provide the necessary electrical connection to the inside plates of the battery.

FIGS. 10 and 11 illustrate the preferred interconnector between the strap 13 with battery plate 41 and upstanding lug 24, and back disk 18. Lug 24 is provided with hollow tapering projection 28 which is accommodated by ball type socket 29 in back disk 18. A portion of ball 33 will fit within the passage 36 of projection 28 and annual wall 37 of projection 28 will fit snugly into and against cricumferential wall 50 of disk 18. With projection 28 so orientated within wall 50, a gun-type welding operation will be effected to weld lug 24 to disk 18. This will be accom plished by utilizing a force of 250 pounds and a welding current of 11,000 amps for 22 cycles. Alternatively, the interconnections and procedures described in U.S. 3,313,658 and U.S. Application Ser. No. 132,660 filed Aug. 21, 1961 can be substituted for making the connection between disk 18 and lug 24. This connection will be electrically tested and then the remainder of the battery cells will be preferably interconnected by the apparatus set forth in U.S.

4 3,544,754. A completed battery unit results with the placement of the appropriate cover.

The apparatus which can be advantageously employed for performing the method of this invention is described in FIGS. 4, 6, 7 and 8. As other apparatus could be employed to perform the same functions, they are merely shown diagrammatically. Referring to FIG. 4, a casting machine generally 30 is described for fabricatingfront button 15. This machine is of the sliding mold variety and has a stationary mold half 31 and a movable mold half 32. A mold insert 34 is provided in mold half 31 for molding the front portion of front button 15. Insert 34 has a projection 35 for receiving a threaded steel nut 38 with an internal steel threaded plug 39 which will rest on a reduced diameter portion 40 of projection 35. Movable mold 32 will ride upon and be guided by lateral lead supports such as shown at 42 and 43. With mold half 32 moved in the position so as to abut against mold half 31, molten lead will be poured along a guide path surface 44 and will enter the mold cavity containing nut 38 to result in the front button 15 as shown in FIG. 5. After solidification of the molten lead, mold half 32 will be moved away from mold half 31 and will carry nut 38 with it to be ejected from the mold half 32 by means of a knockout pin 45 which along with the insert 46 provides the mold half for molding the extending section 16 of front button 15. With movement of knockout pin 45 toward mold half 31, the front button 15 will drop down chute 47 and out of the casting machine, it being recognized that a suitable supporting underframe 48 supports the mold halves 31 and 32 and in the instance of stationary mold half 31, it is secured at the top by means of bar 49. The back button as shown in FIG. 5 by the numeral 18 will be cast in a similar manner. It will also be noticed with reference to FIG. 5, that front button 15 will be molded with lateral projections 21 near the front face 22 of button 15 for accommodation by locating and stabilizing grooves 25 in annulus 12 projecting from side wall 11. It will be seen that the main body section 1 7 of front button 15 is molded with an annular groove 26 adjacent the area where extension 16 projects from main body 17. This annular groove 26 is formed by the projecting annulus 49 of insert 46 in movable mold 32. To aid in the sealing of front button 15 in wall 11, a pointed projection 27 of the annular type is molded adjacent the groove 26 for piercing engagement with endwall 11.

Referring to FIG. 6, a mechanism is indicated for application of wax bead 20 in annular groove 26. The bead 20 is applied by means of a pneumatically operated applicator generally 52 having a head portion 53 with an applicator nozzle 54, which applies the wax in a fluid and melted condition. The applicator 52 remains stationary while front button 15 is rotated on a revolving spindle 55 which is rotatably supported on revolving table 56. Rotation of spindle 55 is afforded by means of rotator 58 with drive wheel 59 turning driven wheel 57.

In FIG. 7, a ram welding device generally 60 is shown as well as a battery container generally 10, the latter being shown in broken lines for welding and application of the squeezing force in two sequences. The ram welder 60 is of the general type described in U.S. Pats. 2,905,804 and 2,958,757. It has two separate force applying means for moving piston rod 62 downwardly and in the direction of lower end or anvil tip 63. The force for moving piston 62 is afforded by a first main piston assembly 64 and a second diaphragm type actuation means 65. Welding current is supplied in the usual manner to welding tip 68 on piston rod 62 by means of bus bar 69 electrically connected to tip 68. Water cooling of the lower tip 63 is afforded through hollow horn support member 69. When the front and back buttons are positioned in annulus 12 of wall 11 (the olientation of which is basically shown in FIG. 5) tip 63 will contact the back of button 18 and welding tip 68 will contact the front 22 of front button 15.

Piston assembly 64 will then move piston rod'62 downwardly to engage front button 15 and welding current will then be supplied to fuse the two buttons together. During the application of welding current under the conditions previously indicated, diaphragm assembly 65 will also be actuated which will apply additional force to piston rod .62 so as to better force the two buttons together while in a fluidized condition.

After the ram welding operation described in conjunction with FIG. 7, the container will be moved to the swaging step which is performed by the device generally 80 shown in FIG. 8. The container 10 with the button welded in annulus 12 will move along conveyer mechanism generally 82 having moving chains 83 and 84 supported by sprockets 85 and 89, respectively, to a position where the annulus 12 housing front button 15 and with the back button 18 welded to the rear thereof will be vertically aligned below anvil surface 86 and hydraulic piston assemblies 87 and 88, it being understood that a complementary anvil similar to that of 86 (not shown) will be oppositely disposed from hydraulic piston 88. By means of suitable automatic controls contained in control box 90, piston assemblies 87 and 88 as well as oppositely disposed anvils 86 will be lowered by means of movable head assembly 92 to position anvils 86 to the rear of the rear button 18 and piston assemblies 87 and 88 with complementary piston rods (not shown) opposite to the front of front button 15. When the container is suitably clamped such as between clamp bar 93 and an oppositely disposed container 10, piston assemblies 87 and 88 will be actuated to as to cause their respective pistons to engage the front of buttons 15 and to force front and back buttons 15 and 18, respectively, between the pistons and the anvils 86 thereby mechanically upsetting them. After the swaging or upsetting step is performed under the previously stated conditions, the piston assemblies 87 and 88 will be deactuated and the head assembly raised so as to permit container 10 to move laterally out of position along convever 82.

Subsequent to the swaging operation, the next procedure is to have the internal cells with their respective lugs such as 24 and straps such as 13 welded to the back 'of back button or disk 18 such as shown in FIG. 11. This is accomplished by a welding head schematically shown in FIG. 9 which has a pneumatic piston chamber 100 for moving piston rod 101 with welding electrode 102 disposed on the end thereof. Rod 101 moves in the direction of anvil 103 which is oppositely supported by a U-shaped member 104. It should be understood that other types of welding devices which will provide both a welding current and a force squeezing movement can be utilized to secure the plate lugs 24 to disk 18. The head assembly 105 shown in FIG. 9 is easily adaptable to the swaging device shown in FIG. 8 and merely requires the substitution of head 105 for piston assemblies 87 and 88 and anvils 86 with the connection made to the head assembly 80 by means of the top of U-shaped support 104.

In describing the method of this invention, the two button 15 and 18 terminal construction has been indicated for use through a passage 14 wherein an annulus 12 surrounds the passage. It should be understood that the use of the annulus 12 while giving an aesthetic effect and affording some protection to the front button 15 is not essential and can be eliminated. The same is true regarding the use of plugs 39 in nut 38. The purpose of plug 39 being merely to keep the threads of nut 38 in a clean and unobstructed condition during the casting step. A wax head 20 has been indicated for use as a sealing means in connection with front button 15 and is indicated as being of a thermoplastic material. It should be understood that other similar types of sealing compositions such as wax, coal-tar base resins, or thermoresins can be substituted which will exhibit viscosity characteristics which resist cold flow under pressure, ad here to polypropylene and metal alloys and produce a fluid tight seal. A pointed projection 27 is illustrated on front button 15 for purposes of affording extra sealing with the plastic wall 11. This can also be eliminated as well as the locator tabs 21 on front button 15. A flat end surface is shown for extension 16 on button 15 and a concave inner surface for back disk 18. If desired, the end surface for button 15 could be made slightly concave and the inner surface of disk 18 flat and still accomplish the desired connection of the this invention.

The front and back buttons have been stated as being composed of a 3% lead antimony-alloy. However, other metallic alloys can be utilized in the steps of this invention such as calcium-lead and tin-lead. In describing the ram weld step where the force and current are simultaneously applied and the force is applied in a two step manner during application of the welding current, it should be pointed out that while this is the prefrred manner, the welding could be effected with the application of a single force and the welding current. Similarly, the welding current is stated as being applied for approximately half of the time that the force is applied. This can also be altered so that the welding time could be of the same duration a the force and can range from 24 to 30 cycles or 24/60 to 30/60 seconds. A welding current of 16,500 amps is indicated and this also can range from 15,000 to 16,500 amps as can the time after the welding step until the swaging step is performed. This duration can be from 2 minutes to 24 hours. A force of some 4000 pounds has been indicated for the swaging step for a period of 1.5 seconds. This can be varied from 4000 to 5000 pounds for a period of /2 to 15 seconds if desired.

It will thus be seen that through the present invention, there is provided a method for applying a front terminal connection for a lead acid battery wherein a metallic part can be securely fastened through the wall of a plastic container and in a leakproof manner. The method involves the construction of a threaded terminal where the threaded portion is protected against thread damage or obstruction. The method of this invention also lends itself to being highly adaptable to automated techniques so that human error is reduced. Further, the method does not nvolve a high capital expenditure for equipment as existing equipment can be readily adapted to perform the various steps.

The foregoing can now be practiced by those skilled in the art. Such skilled persons will know that the invention is not necessarily restricted to the particular embodiments herein. The scope of the invention is to be defined by the terms of the following claims as given meaning by the preceding description.

CLAIMS 1. A method of making a battery terminal connection through an opening in a battery case wall comprising positioning a first member on one side of said wall, said first member having a main body section and an extending sec tion adapted to be positioned in said opening. placin said extending section in said opening and through said wall with a portion of said section projecting from the op posite side of said wall, placing a second member over said extending section of said first member, said second member being fabricated with an accommodating compartment for frictionally engaging said extending section of said first member, fluidizing with force the contacting portions of said first and second members and plasticizing a portion of said wall between said first and second members, permitting the fluidized contacting portions to cool and forcing said first and second members together with a portion of said fluidized wall in between.

2. The method as defined in claim 1 further including the step of fabricating said first member with a nut therein and with a threaded plug carried by the nut during the fluidization of the contacting portions of the first and second members and the forcing step. v

3. The method as defined in claim 1 further including the step of applying an annular bead of wax to said first member at a position where the extending section projects from the main body section of the first member.

4. The method as defined in claim 1 further including the application of additional force between said first and second members after said initial fluidization with force and before said forcing step after the cooling of the members.

' 5. The method as defined in claim 2 wherein said first effected during about a V2 second to about a 15 second time interval.

8. The method as defined in claim 7 wherein said forcing step after cooling of the first and second members is efiected in the range of about 2 minutes to 24 hours after the fluidization with force step.

9. The method as defined in claim 3 further including the step of fabricating the first member with an annular groove at a position where the extending section projects from the main body section and applying said Wax head in said groove.

10. The method as defined in claim 7 wherein said forcing step after cooling of said first and second members is effected at a force of about 4000 pounds.

11. The method as defined in claim 1 wherein said second member is secured to a lug of a battery plate by means of a ball and socket type connection and welding with force.

References Cited UNITED STATES PATENTS 3,388,005 6/1968 Hahn et al. 136 134 R 3,544,754 12/1970 Buttke et a1. 136176 X 3,607,441 9/1971 Mix 136176 3,687,734 8/1972 Orlando et al. 136-134 R 3,736,191 5/1973 Blandf-ord l36l35 S 3,767,467 1'0/1973 Miller et al. l36-l35 S 3,770,510 11/1973 Sabatino 136-176 X 25 ANTHONY SKAPARS, Primary Examiner 

1. A method of making a battery terminal connection through an opening in a opening in a battery case wall comprising positioning a first member on one side of said wall, said first member having a main body section and an extending section adapted to be positioned in said opening, placing said extending section in said opening and through said wall with a portion of said section projecting from the opposite side of said wall, placing a second member, said second member being fabricated with an accommodating compartment for fictionally engaging said extending section of said first member, fluidizing with force the contacting portions of said first and second members plasticizing a portion of said wall between said first and second members, permitting the fluidized contacting portions to cool and forcing said first and second members together with a portion of said fluidized wall in between. 